802.11 Wireless Network Standards
laptops now contain Wi-Fi capability and wireless connectivity for computers
is thus well established. The IEEE 802.11 standard, also referred to as
Wi-Fi is now an accepted standard for WLAN solutions that are available. Wi-Fi
is able to compete well with wired systems because operating speeds of
systems using the IEEE 802.11 standards of around 54 Mbps is now common.
Wi-Fi hotpots are found in abundance and in common use due to the
flexibility and performance of the system. Laptop computers can be now
used while waiting in hotels, airport lounges, cafes, and other places using
a wireless link rather than using a cable.
used for temporary connections, and for temporary Wireless Local Area
Network, WLAN applications, the 802.11 standards can also be used for more
permanent installations. WLAN equipment can be used in offices to provide
semi-permanent WLAN solutions. WLAN equipment use enables offices to be
set up without requiring permanent wiring, which results in a considerable
cost saving. WLAN equipment allows changes to be made around the office
without the need to re-wiring.
Due to this the
Wi-Fi IEEE 802.11 standard is used commonly to provide WLAN solutions both
for temporary connections in hotspots in cafes, airports, hotels and
similar places and also within office scenarios.
All the 802.11
Wi-Fi standards operate within the ISM (Industrial, Scientific and
Medical) frequency bands. License is not required for operation within
these frequencies, and these are shared by a variety of other users which
makes them ideal for a general system for widespread use.
802.11b, 802.11g, 802.11n & 802.11ac:
A number of
bearer standards that are in common use. Each standard was launched at
different times and have different features. 802.11
is the collection of standards setup for wireless networking. The most
common and popular standards out of these are 802.11a, 802.11b, 802.11g,
802.11n and 802.11ac providing raw data rates of up to 600 Mbps. A frequency is used by each standard to connect
to the network which has a defined upper limit for data transfer speeds.
was one of the first wireless standards. 802.11a can achieve a maximum of
54Mbps and operates in the 5Ghz radio band. It was not as popular as the
802.11b standard due to higher prices and lower range. It operated in the
5 GHz ISM band rather than the 2.4 GHz band, which made chips more
expensive and never caught on in the same way as 802.11b even
though it offered a much higher data transfer rate. Pros of 802.11a: Fast maximum speed; regulated frequencies
prevent signal interference from other devices. Cons of 802.11a: Highest cost; shorter range signal that is
more easily obstructed.
supports up to 11 Mbps and operates in the 2.4Ghz band. It has a
theoretical range of up to several hundred feet. It was the first real
consumer option for wireless and very popular. 802.11b uses the CSMA/CA
technique for transmitting data, that was defined in the original 802.11
base standard and retained for 802.11b. With this technique, when a node has
to make a transmission it listens for a clear channel and then transmits. Then
it looks for an acknowledgement and if not received it holds back for a
random time period, assuming interference is caused by another transmission,
and then listens for a clear channel and then retransmits the data. Pros of 802.11b:
Cost is among lowest; has a good signal range and not easily obstructed. Cons of
802.11b: Maximum speed is among slowest; home appliances could
interfere on the unregulated frequency band.
channels in 2.4GHz band:
802.11g – While
operating on the 2.4 GHz ISM band in order to provide the higher speeds of
802.11a, a new standard was introduced – known as 802.11g, it soon took
over from the b standard. 802.11g uses the
2.4 GHz frequency for greater range and
supports bandwidth up to 54 Mbps. Since it operates in the same band as
802.11b, 802.11g is backward compatible with 802.11b, so that
points will work with 802.11b wireless network
adapters and vice versa.
802.11a is not directly compatible with 802.11b or 802.11g since it
operates in a different band. The 802.11b standard became the most
popular operating in the 2.4 GHz ISM band post the introduction of Wi-Fi
with the 802.11a and 802.11b standards. This standard became the most
popular despite the faster operating speed of 802.11a because the cost of
producing chips to operate at 2.4 GHz were much less than ones to run at 5
GHz. Pros of 802.11g: Fast
maximum speed; signal range is good and not easily obstructed. Cons of 802.11g: Costs more than
802.11b; appliances may interfere on the unregulated signal frequency.
Wireless network bearer has up to 600 Mbps data rates and operating in the
2.4 & 5 GHz ISM bands. After establishing the Wi-Fi standards of
802.11a, 802.11b, and 802.11g, efforts were begun to look at how raw data
speeds provided by Wi-Fi, 802.11 networks could be increased more. As a
result in January 2004 the IEEE announced forming a new committee to
develop the new high speed, IEEE 802.11n standard. In early 2006, the
industry mostly agreed about the features for 802.11n. The standard soon became widespread with many
products offered for sale and use with the improved performance offered by
802.11n. Although initially few Wi-Fi hotspots offered the standard,
802.11n devices were compatible and able to work with the 802.11b and
802.11g based hotspots. Also referred to as “Wireless N”,
802.11n was designed to
improve on 802.11g in the amount of bandwidth supported by utilizing
multiple wireless signals and antennas (called MIMO technology) instead of one. 802.11n was ratified
by industry standards groups in 2009 with specifications providing for up
to 300 Mbps of network bandwidth. Better range over earlier Wi-Fi
standards was offered by 802.11n due to its increased signal intensity,
and it is backward-compatible with 802.11b/g gear. Pros of 802.11n: Fastest maximum speed and best signal range;
more resistant to signal interference from outside sources. Cons of 802.11n:
Costs more than 802.11g; the use of multiple signals may greatly interfere
with nearby 802.11b/g based networks.
802.11ac – The newest generation of Wi-Fi signaling
in popular use, 802.11ac utilizes dual-band
wireless technology, supporting simultaneous connections
on both the 2.4 GHz and 5 GHz Wi-Fi bands. 802.11ac offers backward
compatibility to 802.11b/g/n and bandwidth rated up to 1300 Mbps on the 5
GHz band plus up to 450 Mbps on 2.4 GHz. The
standard was developed from 2008 (PAR approved 2008-09-26) through 2013
and published in December 2013 (ANSI approved 2013-12-11).
IEEE Standards for Local and Metropolitan Networks: Demand Priority Access Method,
Physical Layer and Repeater Specification for 100 Mb/s Operation
Scope: The standard covers
the protocol & compatible interconnection of data communication
equipment via a repeater-controlled, star-topology Local Area Network
(LAN) using the demand-priority access method.
Purpose: To provide a
higher LAN speed with deterministic access, optional filtering and priority.
priority is the media access control protocol used by the new 100 Mb/s 100
VG-AnyLAN network being standardised by the IEEE 802.12 committee. The network can interconnect hubs in multiple wiring
closets (without bridging or routing), and can have a network diameter of
several kilometers. The IEEE 802.12 standard, called 100VG-AnyLAN is intended to provide a high-speed network that can
operate in mixed Ethernet and Token Ring environments by supporting both
The IEEE 802.x
specifications are a group of network standards defined by ISO. 802.12 covers
the low level – Data Link Layer. The Data Link Layer is divided into 2
Link Control (LLC). This sublayer establishes the transmission paths between
computers on a network.
Access Control (MAC). On a network, the network interface card (NIC) has an
unique hardware address which identifies a computer or peripheral device. The
hardware address is utilized for the MAC sublayer addressing.
The IEEE 802.12
100 VG – AnyLAN is a high-speed network with a data rate of 100 megabits
per second (Mb/s) which can be transmitted over several types of twisted
pair cable including single or multiple mode fiber optic cable. The
100VG-AnyLAN data packets can be encapsulated by IEEE 802.5 Token Ring or
IEEE 802.3 Ethernet frames. The packets can also be routed across FDDI,
ATM, and wide area networks. For media access, a packet is formatted with
a training frame that is initially utilized by the IEEE 802.12 interface.
This initialization determines whether the packet is normal or high
priority (for example, multimedia video or audio data) according to the
Demand Priority Access Method media protocol (DPAM).
IEEE 802.13 – not used due to the number 13 being
The IEEE 802.14 –
Cable modems. Defined
in 1996, deals with digital transmission of cable TV networks. Withdrawn
PAR. It is not endorsed by the IEEE any more.
the 1990s a subcommittee (802.14) was formed to develop a standard
for cable modem systems. IEEE 802.14 developed a draft ATM-based
standard. But, the 802.14 working
group was disbanded as North American multi
system operators (MSOs) instead supported the then fledgling DOCSIS 1.0 specification, which mostly used best efforts service and was IP-based (having extension codepoints to
support ATM for QoS in the future). MSOs wanted
to quickly deploy service to compete for broadband Internet
access customers instead of
waiting on the slower, iterative, and deliberative processes of standards
The IEEE 802.15
Personal Area Networks (WPANs) is covered by this group – Communications
specification that was approved in early 2002 by the IEEE for wireless
personal area networks. Different technologies are covered by several
802.15.1 – Bluetooth
based. Short range (10m) wireless technology for cordless keyboard,
mouse, and hands-free headset at 2.4 GHz.
802.15.3a – To provide a higher speed Ultra wideband (UWB)
PHY enhancement amendment to IEEE 802.15.3 for applications which involve
imaging and multimedia. Short range, high-bandwidth “ultra
wideband” link. This was withdrawn
in January 2006
802.15.4 – ZigBee.
Short range wireless sensor
802.15.4 is a technical
standard covering the operation of low-rate wireless personal area
networks (LR-WPANs). This standard was defined in 2003 and maintained
by the IEEE 802.15 working group, it covers the physical layer and media access control for LR-WPANs. It forms the
basis for the ZigBee ISA100.11a, WirelessHART, MiWi, SNAP, & Thread specifications, each
of which further extends the standard by developing the upper layers which
are not defined in IEEE 802.15.4. It can also be used with 6LoWPAN,
the technology used to deliver the IPv6 version
of the Internet Protocol (IP) over WPANs, to define the upper
Network. Extension of network coverage without increasing the transmit
power or the receiver sensitivity; Enhanced reliability via route
redundancy; Easier network configuration –
Better device battery life.
provides the architectural framework enabling WPAN devices to promote
interoperable, stable, and scalable wireless mesh networking. It is composed of two parts: (i) low-rate WPAN
mesh less, which is built on IEEE
802.15.4-2006 MAC, and (ii)
high-rate WPAN mesh networks which utilize IEEE 802.15.3/3b MAC. Common
features of both meshes include network initialization, addressing, and
multihop unicasting. In addition, the low-rate mesh supports multicasting,
reliable broadcasting, portability support, trace route and energy saving
function, and the high rate mesh supports multihop time-guaranteed
XVIII. EEE 802.16
is a series of wireless broadband standards for broadband for
wireless metropolitan area networks. The 802.16 standard essentially
standardizes two aspects of the air interface – the physical layer (PHY)
and the media access
control (MAC) layer.
Covers both OFDM and OFDMA physical layers.
OFDM is referred as fixed wimax and OFDMA as mobile wimax. This
family of standards covers Fixed and Mobile Broadband Wireless Access
methods used to create Wireless Metropolitan Area Networks (WMANs.)
– Draft Standard for Air Interface for Broadband Wireless Access Systems
approved by IEEE: The standard promotes early and fast deployment all over the world, of ingenuous and
cost reasonable, and interoperable multivendor broadband wireless access
products, and encourages competition in broadband access by alternatives provisioning
to wireline broadband access, encourages regular and constant worldwide
spectrum allocations and speeding up commercialization of broadband
wireless access systems.
Ring. 802.17 A new ring topology network architecture, called the
Resilient Packet Ring (RPR), is standardized to be used primarily in
metropolitan & wide area networks.
rings are widely deployed in Metropolitan and Wide Area Networks. Protocols
that are neither optimized nor scalable to the demands of packet networks are
presently being used by these rings, including speed of deployment,
bandwidth allocation & throughput, resistance to faults, & lower
equipment and operational costs.
802.17 Resilient Packet Ring Working Group defines standards to
support the development and deployment of Resilient Packet Ring (RPR)
networks in Local, Metropolitan, and Wide Area Networks for resilient and
efficient transfer of data packets at rates scalable to many gigabits per
second. Existing Physical Layer specifications are built upon by these
standards, and new PHYs where appropriate are developed. IEEE 802.17 is a part
of the IEEE 802 LAN/MAN Standards Committee.
(RPR) protocol is
a ring based network protocol designed for
the optimized transport of data traffic over optical fiber ring networks. The design is to provide the resilience found in SONET/SDH networks
(50 ms protection) but, provides a packet based transmission instead
of setting up circuit oriented connections, aiming to increase the
efficiency of Ethernet & IP services.
Similar to other
IEEE 802 standards, IEEE 802.17 has both a physical and a medium access control (MAC) layer. An important feature
of the physical layer is the use of a dual-ring topology using optical
fiber at high data rates, up to 1 Gbps or more. Data can be transmitted
simultaneously on both rings in normal operation, doubling the capacity. Robustness
is provided by the dual-ring topology by including a capability for
automatic reconfiguration after a link failure.
The main purpose
is to provide enhanced services for the transmission of Ethernet packets
over a ring-based interconnect topology at the MAC level. This means a
simple mapping from the Ethernet frame format to the RPR frame format.
runs on a concept of dual counter rotating rings referred to as ringlets.
These ringlets are set up by creating RPR stations at nodes where traffic
is supposed to drop, per flow (a flow is the ingress and egress of data
traffic). Media Access
Control protocol (MAC) messages
to direct the traffic, is used by RPR, which can use either ringlet of the
ring. The nodes also negotiate for bandwidth among themselves using
fairness algorithms, avoiding congestion & failed spans. Failed spans are
avoided by using one of two techniques known as steering & wrapping.
All nodes are notified of a topology change & they reroute their
traffic if a node or span is broken under steering. The traffic is looped
back, in wrapping, at the last node before the break & routed to the